Method and apparatus for wrapping tensioned wire around vessels



A. BRANDESTINI 3,452,940 METHOD AND APPARATUS FOR WRAPPING TENSIONED WIRE AROUND VESSELS Filed on. 18, 1965 of 4 Sheet July 1, 1969 INVENT OR July 1, 1969 A. BRANDESTINI 3,452,940

I METHOD AND APPARATUS FOR WRAPPING TENSIONED ,8 I of 4 t e e h S s L E s S E v D N U 0 R A 4 E R I W Filed Oct. 18, 1965 y 1969 A. BRANDESTINI 3,

METHOD AND APPARATUS FOR WRAPPING TENSIONED WIRE AROUND VESSELS 3 Filed Oct. 18, 1965 Sheet of 4 July 1, 1969 A. BRANDESTINI 3,452,940

METHOD AND APPARATUS FOR WRAPPING TENSIONED WIRE AROUND VESSELS Sheet 4 of 4 Filed Oct. 18, 1965 Ii Illllllll United States Patent US. Cl. 242-7.01 2 Claims ABSTRACT OF THE DISCLOSURE A method and apparatus for winding a tensioned wire within the grooves of a peripherally grooved container. One end of a wire supply is secured to the container at a location adjacent the groove and a winding apparatus is displaced about the container adjacent the groove to continuously draw off wire from the Wire supply. The rate at which the wire is drawn off is controlled so as to apply a predetermined tension to the wire wound about the container. Guiding means are provided for the tensioned Wire in the groove so that the Wire builds up within the groove in layers. The winding apparatus located adjacent the groove has driving means cooperating with the winding means to displace the winding means about the container at a speed greater than the speed at which the untensioned wire is drawn from the wire supply. Spooling means are provided for guiding the tensioned Wire from one side to the other side of the groove. Wire anchorages are provided abjacent the groove for anchoring ends of the tensioned wire The present invention refers to a method and apparatus for wrapping tensioned wire around a relatively rigid object, and in particular, for Wrapping tensioned wire within grooves formed in the outer surface of concrete pressure vessels.

Trends in the development of pressurized concrete vessels, for use particularly in the field of nuclear power generation, require the pre-tensioning of vessels of pseudospherical form in which the final shape of the vessel is determined by a multiple step formation of its outer surface. Such vessels may be of large size with diameters of the order of 100 feet. A further application of such vessels is in the storage of liquids and of liquefied gases under pressure.

It has been found that the pre-tensioning of such vessels is conveniently achieved by winding wire in grooves formed in the successive stops forming the pressure vessel.

Two main objects of the present invention are to pro vide a method and appartus for winding a tensioned Wire within the grooves of a peripherally grooved container.

A further main object of the invention is to provide a wire anchorage adapted to anchor tensioned wire in the grooves of a peripherally grooved container.

According to the invention a method of winding a tensioned wire within the grooves of a peripherally grooved container comprises the steps of securing one end of a wire supply to the container at a location adjacent a said groove, displacing a winding unit about the container adjacent said groove to continuously draw off wire from the wire supply, controlling the rate at which Wire is drawn off the wire supply to be less than the rate of displacement of the winding unit about the container so as to apply a predetermined tension to the wire wound about the container, and guiding the tensioned wire from side to side of the groove so that the wire builds up within the groove in layers.

The invention also provides a machine for winding pretensioned wire within the grooves of a peripherally grooved container comprising a wire supply source, a winding means adapted to be located adjacent a sa d groove for winding wire from the Supply source within said groove, drive means co-operating with the winding means to displace the winding means about the container at a speed greater than the speed at which untensioned wire is drawn from the Wire supply source, and spooling means movable with said winding means and operable to guide the tensioned wire from one side to the other side of the groove so that said wire may be built up within the groove in layers.

The invention further provides a prestressed peripherally grooved container wound by a method and apparatus as described in the last two preceding paragraphs.

The invention also provides a wire anchorage adapted to anchor tensioned wire in the grooves of a peripherally grooved container comprising a first and a second anchorage block each adapted to be secured with the wall of said container adjacent a recessed portion of a said groove such that the block does not protrude above the level of a side of the groove, a plurality of slots in each said block, each slot being adapted to receive an end of a tensioning wire, and an attachment button adapted to be secured to one said wire end to transmit tension in the wire to said first anchorage block, portions of the second block forming the sides of the slots therein being adapted to be folded about the other wire end to clamp said other wire end firmly to said second block.

The invention also provides a prestressed peripherally grooved container comprising a wire anchorage as described in the last preceding paragraph.

In order that the invention may be clearly understood one embodiment thereof will now be described by Way of example, with reference to the accompanying drawings in which:

FIGURE 1 is an elevation of a wire wrapping machine according to the invention shown in position on a container to be wrapped.

FIGURE 2 is a plan view of the wire wrapping machine of FIGURE 1.

FIGURE 3 is an elevation of a groove in a peripherally grooved container showing two wire anchorages.

FIGURE 4 is a cross section of the groove taken on the line 44 of FIGURE 3, and

FIGURE 5 is a diagram illustrating the sequence of wire anchorage points around a groove in a wrapped container.

Referring now to FIGURE 1 of the drawings it will be seen that the winding means is formed by a carriage arranged to move on and around a concrete pressure vessel 1 adjacent a groove 2 formed in the outer periphery of the vessel. The carriage 3 is provided with two rollers 4 which ride on a lower side of the groove 2, and with rollers 5 which ride on the outer surface of the vessel 1. Upon these rollers the entire carriage unit can revolve about the periphery of the vessel 1. In order to facilitate revolving of the carriage unit about the vessel, a suitable adjustable ar-m member (not shown) pivoted about approximately the centre line of the container may be provided, in a manner taught in US. Patent 2,785,866.

A drive motor 6, which may be any convenient prime mover, for example, petrol or diesel powered, is arranged on the carriage 3, which may also carry a cable guide in the case of an electric drive motor 6. The motor 6 drives a won-m and bevel gear 7 through a shaft 8, thereby motivating a pully 9 via a slipping clutch 10, and also driving a sprocket 11 whose effective diameter is slightly greater than that of the pulley 9. The pully 9 and sprocket 11 are carried upon a shaft 12 housed in bearings 13.

A similar assembly of pulley 14, slipping clutch 15 and sprocket 16 are mounted upon a non-driven shaft 17 housed in bearings 18. The pulleys 9, 14 have a plurality of separate grooves formed on their periphery, and they are of equal diameter.

Also upon the carriage is mounted a wire supply formed by a reel .19 mounted upon a bearing 20 having in association therewith a reel brake (not shown) which exerts a weak braking effect to prevent unwanted uncoiling of wire from the reel 19.

Wire 33 uncoiling from the reel 19 passes through a wire guide and 'brake unit 21 which exerts a further braking action on the wire. The wire then passes about the top grooves of the two pulleys 9, 14, then about successive lower grooves of the pulleys until the wire leaves the bottom groove of the pulley 9, which is aligned substantially on the centre line of the groove 2 in the vessel 1. The wire then passes through a wire guide unit 22 and a guide 23 forming part of a spooling unit before being wound under tension in the groove 2 of the vessel 1.

As shown in FIGURE 2, in order to produce rotational movement of the carriage unit 3 about the concrete vessel 1, there is provided a drive means formed by an endless chain 24 slung about the outer wall of the concrete vessel 1. The endless chain 24 engages with the driven sprocket 11, the non-driven sprocket 16, and a jockey sprocket 25 which serves to tension the chain under the action of the spring 26. The jockey sprocket 25 is mounted upon a hearing 27 movable in a slot 28 in the carriage frame.

If the container to be pre-tensioned is a pressure vessel having its outer surface formed in steps of varying diameter provision is made for additional links of the chain 24 to be inserted when the carriage 3 is moved from a groove in one step of the vessel to a groove in a step of greater diameter.

The spooling means 29 attached to the carriage 3 is operative to move the wire guide 23 in a vertical direction by an increment substantially equal to the width of the wire each time the carriage has made one revolution around the vessel 1. In order to achieve this result the spooling means 29 comprises a screwed shaft 31 located within a vertical slot 30, and a threaded slider 32 attached to the guide 23 rides upon the screwed shaft 31.

To the upper end of the shaft 31 is attached a collar carrying four actuating arms 34. Two adjacent links of the endless chain 24 are arranged to carry upstanding striker pins 35, which strike the actuating arms 34 and so rotate the shaft 31 at each revolution of the carriage 3. The pitch of the screw-thread on the shaft 31 is arranged to be such that the guide 23 is moved vertically a distance equal to the gauge of the wire 33 at each revolution of the carriage, and in this way even and close spooling of the wire within the groove 2 is achieved.

FIGURE 3 shows the location of two anchoring points 36, 37 each adapted to anchor at number of lengths of wire wound within a groove 2. The anchoring points 36, 37 are seen to lie on opposite sides of the groove 2. In the presently described embodiment separate layers of tensioning wire are wound across the width of the groove between two such anchoring points. After winding each layer, the guide 23 is moved to the lower portion of the shaft 21 prior to winding a further layer of wire within the groove.

If the guide 23 is not moved back, after winding of one layer, to its initial position by turning the shaft 31 in the opposite direction by hand, the shaft 31 can be provided with a so-called continuous double helix track with which an inwardly projecting member of guide 23 is cooperating, the guide 23 thereby making, with the shaft 31 turning always in the same direction, automatically a to-andfro movement on the shaft.

If it is desired to lay multiple layers of wire within the groove during a single operation of the carriage 3, a double helix of left hand and right hand thread forming a continuous track may be provided on the shaft 31, and

4 the slider 32 may act as a follower to move the guide 23 first in one direction and then in the other between the opposite faces of the groove 2.

In the operation of the machine, wire 33 from the supply reel 19 is passed about the two pulleys 9, 14 and through the various wire guides, and its end is attached to an anchoring point within the groove 2, in a manner to be described.

The length of the endless chain 24 is adjusted by adding or taking way a suitable number of links so that the jockey sprocket 25 is urged by the spring 26 to keep the endless chain 24 in tension and so to hold the rollers 5 of the carriage against the outer wall of the vessel 1.

The motor 6 is now set in operation, turning the pulley 9 to draw wire off the supply reel 19, and to rotate the sprocket 11 thereby moving the carriage about the periphery of the vessel 1.

Since the diameter of the sprocket 11 is slightly greater than the diameter of the pulley 9 the speed of the carriage about the container is slightly greater than the peripheral speed of the pulleys 9, 14. Since it is this latter speed which governs the rate at which wire is unwound from the reel 19 in its untensioned state, the wire leaving the pulley 9 and wound within the groove 2 is extended and so placed in tension.

The slipping clutches 10, 15 are effective to limit the above mentioned tension in the wire to a desired working value, which may be a fixed percentage of the breaking strain of the wire.

At each revolution of the carriage 3, the two striker pins 35 on the chain 24 engage two successive actuating arms 34 on the spooling means, and the guide 23 is moved in an upward direction to permit the next coil of wire to be laid in the groove in side by side relation with the previous coil.

When the carriage has made a number of revolutions about the container corresponding to the number of coils of wire required to cover the width of the groove, the wire is attached in a manner to be described to an anchorage adjacent the upper side of the groove.

A further layer of wire is now wrapped upon the first layer between two further anchoring points at a distance of one quarter of the groove circumference from the original anchoring points. As can be seen from FIGURE 5, successive pairs of anchoring points are arranged at intervals around the groove.

FIGURES 3 and 5 show a preferred form of Wire anchorage and its location in relation to a groove 2.

Referring to FIGURES 3, and 4, a pair of anchorage blocks 36 and 37 are set into the vessel wall so that portions of the blocks protrude from recesses 38, 39 formed in the sides of the groove 2. It will be seen that the blocks do not, however, protrude above the general level of the sides of the grooves. The anchorage blocks comprise an initial anchorage block 36 and a terminal anchorage block 37, each offset along the length of the groove in relation to the other.

The portion of the initial anchorage block 36 protruding into the recess 38 has slots 40 formed therein, the slots having a width slightly greater than the gauge of the tensioning wire. One end of each slot 40 is drilled out to accept a collar 41 on the tensioning wire 33 located within that slot. To the initial end of each tensioning wire 33 is fixed an attachment button 42 Which transmits the tension of the wire to the block 36.

The length of a single run of tensioning wire required to form a single layer of wire across a groove may necessitate a splice 43 (FIGURE 4) being inserted between two lengths of wire carried upon the reel 19 of the carriage 3. If spliced wire is used, the various wire guides forming part of the winding means will be designed to accept such splices.

When a layer of wire has been wrapped across the width of the groove, it is attached to the terminal anchorage block 37. The terminal anchorage block 37 is comparable in its overall dimensions to the initial block 36, but the row of slots 44 formed therein is dimensioned to enable the metal 45 forming the sides of the slots to be folded over after insertion of the tensioning wire, so clamping the wire. After clamping the wire in the terminal anchorage block, the tension in the wire between the winding machine and the block is released and the wire is cut prior to winding a further layer within the groove.

FIGURE 5 shows the sequence of anchorage points utilised in winding consecutive layers of wire within a groove. The first layer of wire wound at the base of the groove is attached to the initial and terminal anchorage blocks 36, 37. The next layer of wire will be attached to the initial and terminal anchorage blocks 46, 47, at a location one quarter of the circumference of the container away from the pair of blocks 36, 37. Subsequent wire layers are anchored at 90 intervals, so that the fifth layer to be wound will again be anchored to the pair of blocks 36, 37.

It will be appreciated that the numbers of anchoring points used, the length and guage of the wire, the sequence and positioning of the anchorage points, and the pattern in which the wire is laid within a groove will be determined in any given case by the size of the vessel to be wound, the internal pressure to be withstood, the material of construction of the vessel, among other factors which will be apparent to those skilled in the art.

I claim:

1. A method of winding a tensioned wire within the grooves of a peripherally grooved container comprises the steps of securing one end of a wire supply to the container at a location adjacent a said groove, displacing a winding unit about the container along a fixed path adjacent said groove to continuously draw off wire from the wire supply, controlling the rate at which wire is drawn off the wire supply to be less than the rate of displacement of the winding unit about the container so as to apply a predetermined tension to the wire Wound about the container, guiding the tensioned wire from side to side of the groove so that the wire builds up within the groove in loyers and thereafter repeating the previous steps in each of the grooves of said container.

2. A machine for winding pretensioned wire within the grooves of a peripherally grooved container comprising:

(a) a wire supply source, and winding means disposed adjacent a given groove of the container for winding wire from said supply source, said wire supply source being mounted on said winding means;

(b) chain means fixed to said container for attaching said winding means to said container;

(c) drive means cooperating with said winding means to displace said winding means along a fixed path about the periphery of said container at a speed greater than the speed at which untension Wire is drawn from said wire supply source;

(d) said driving means comprising:

(1) a driving motor mounted on said winding means,

(2) a winding drum driven by said motor to draw wire from said wire supply source at a first rate of speed,

(3) a sprocket driving wheel driven by said motor at a second rate of speed higher than said first rate of speed, and

(4) said sprocket driving wheel cooperating with said chain means fixed to said container; and

(e) spooling means movable with said winding means and operable to guide the tensioned wire from one side to the other side of said groove in the container so that said wire may be built up within the groove in layers.

References Cited UNITED STATES PATENTS 2,375,921 5/1945 Hirsh 242--11 2,704,191 3/1955 Schley et al. 24286.8 2,785,866 3/1957 Vogt 242-7 2,887,130 5/1959 Kell 52-224 X 3,089,656 5/1963 Crom 242-7 FOREIGN PATENTS 828,135 2/1960 Great Britain.

BILLY S. TAYLOR, Primary Examiner.

U.S. Cl. X.R. 

